￼Whole Body Musculoskeletal Lesions In Military Working Dogs With Versus Without Lower Back Pain.

Introduction/Purpose: Lumbosacral disease is a common cause of lower back pain, disability, and early retirement for military working dogs. Because they are bred and selected for stoicism and high drive, affected dogs may initially mask their lower back pain, develop compensatory gait changes, and place additional stresses on other musculoskeletal structures. A previous study found an association between lower extremity overuse and lower back pain in human athletes (Nadler 1998). The purpose of this prospective cross sectional study was to test the hypothesis that the number of whole body musculoskeletal lesions is associated with lower back pain in military working dogs.

Methods: Whole body computed tomography (CT) scans were acquired for 10 military working dogs presented to the Department of Defense Military Working Dog Veterinary Service at Lackland, TX. Five dogs were presented for lower back pain, and five dogs were presented for other reasons and had no clinically detected lower back pain. All CT scans were acquired using the same 64-slice CT scanner. Scans were archived, stored and transferred to an image analysis workstations (Apple Inc. Cupertino, CA) for analysis using CT image analysis freeware (OsiriX DICOM Viewer, Version 4.2). A board-certified veterinary radiologist unaware of lower back pain status viewed the scans and recorded location and characteristics for all observed musculoskeletal lesions. Lesions were grouped into one of fifteen anatomic region categories (cervical spine,shoulder,carpus,thoracicspine,etc.).Afterallscans were read,thetotalnumber of lesions was determined for each dog and each anatomical region. A statistician performed comparisons between dogs in the lower back pain group versus dogs in the no low back pain group using one-way analysis of variance (ANOVA).

Results: Each group included 1 female and 4 male. Ages ranged from 2 to 10 years , with even distribution of ages between groups. All dogs in the lower back pain positive group were German Shepherds. Dogs in the lower back pain group included 1 German Shepherd, 1 Labrador Retriever, and 3 Belgian Malinois. On average, dogs with lower back pain had a greater number of musculoskeletal lesions (60.6) throughout their whole body than dogs without lower back pain (21) (P=0.003). A significant difference was found in the number of lesions between the two groups for all regions of the spine except the cervical: thoracic (P=0.015), lumbar (P=0.026), lumbosacral (P=0.002), caudal (P=0.010). A significance difference was also detected in the tarsus (P=0.049). No differences were identified between groups for the remaining anatomic regions.

Discussion/Conclusion: Findings supported our hypothesis that lower back pain is associated with the number of whole body musculoskeletal lesions in military working dogs. Findings were not consistent with the previous human study in that spinal regions were primarily affected rather than lower extremities. Further studies are needed to determine if whole body lesions occur in military working dogs before or after the onset of lower back pain. Studies evaluating the relationship between spinal column lesions and lower back pain in these dogs are also needed.